Is Forretress any good

Doesn't excel in any one area (Pinsir and Heracross are superior) but I'd say good for prestiging against Psychic and grass types. Double weakness to fire types so exploitable defender

Prestiging Snorlax and exeggutor.

Resists all of the moves available to Snorlax and Blissey, except for Lick and Earthquake which are neutral. Don't know whether its attack is high enough to beat Blissey in time though.

You need Heavy Slam. Preferably Bug Bite/Heavy Slam.